By Dave Sebastian

Quantum-computing company Rigetti & Co. Inc. is going public by combining with special-purpose acquisition company Supernova Partners Acquisition Co. II Ltd., a deal that would value the combined entity at about $1.5 billion.

The companies Wednesday said the deal would provide about $458 million in gross proceeds, including $345 million in cash held in the SPAC's trust account.

The combined entity would take the name of Rigetti Computing Inc. and trade on the New York Stock Exchange under the ticker RGTI after the deal closes, the companies said.

Founded in 2013, Rigetti said it will use the proceeds to accelerate the development of quantum processors and grow its commercial business. It said it expects to scale its quantum computers from 80 qubits in 2021 to 1,000 qubits in 2024 and 4,000 qubits in 2026.

The private investment in public equity transaction, which gives cash proceeds of about $100 million, involves T. Rowe Price Associates, Inc., Bessemer Venture Partners, Franklin Templeton and In-Q-Tel. Strategic investors include Keysight Technologies and Palantir Technologies, and Ampere Computing will make a direct investment, the two combining companies said.

Rigetti said it has raised about $200 million in venture capital and employs more than 130 people with offices in the U.S., Canada, the U.K., and Australia.

Michael Clifton, who leads the SPAC and recently helped lead global technology investing at the Carlyle Group Inc., is expected to join Rigetti's board after the deal closes, the companies said.

SPACs, which are shell companies that raise money with the sole purpose of looking for a target to merge with and take public, have risen in popularity as companies seek alternatives to a traditional initial public offering.

Write to Dave Sebastian at dave.sebastian@wsj.com

(END) Dow Jones Newswires

10-06-21 0843ET